Plant Pathology Commons^™

Ploidy Level And Competitive Response In Dactylis Glomerata L., N Maceira, P Jacquard, R Lumaret

IGC Proceedings (1977-2023)

Dactylis glomerata L is a widely distributed autopolyploid complex, which includes mainly diploid and tetraploid cytotypes. In Galicia (Spain), morphologically indistinguish­able and genetically very closely related diploid and tetraploid plants are sympatric, but they differ in habitat preference and life-history traits (Lumaret et al., 1987). Diploids are usually confined to low density forest understories of Quercus robur, while tetraploids are predominant in open areas with more dense herbaceous vegetation. Rothera and Davy (1986) found a similar habitat distribution in other polyploid complex (Deschampsia cespitosa) and suggested that diploids might be more sensitive to competition than tetraploids. Tetraploid …

Potential Uses Of Embryo Culture Derived Interspecific Hybrids Of Alfalfa (Medicago Sativa L.), T J. Mccoy, L J. Mancino

IGC Proceedings (1977-2023)

Interspecific hybridization has frequently been used in crop improvement programs to introgress economic traits from wild species into the cultivated germplasm pool. In alfalfa (Medicago sativa) unadapted accessions have been important sources of disease resistance and winterhardiness. However, unadapted germplasm sources used in alfalfa improvement to date have been limited to the M. sativa complex (McCoy and Bingham, 1988) A number of valuable traits have been ident­ified in other Medicago species (summarized in McCoy, 1985) but the obstacle to using other species had been the inability to recover interspecific hybrids.

Recently, the limits of crossability in the genus …

Seasonal Changes In Palatability Of Hybrids Between Phalaris Aquatica And Hexaploid P. Arundinacea, R N. Oram, H E. Schroeder

IGC Proceedings (1977-2023)

F 1 hybrids between P. aquatica L. and the hexaploid (6x) race of P. arundinacea L. produce more herbage than their parents in summer and autumn in south-eastern Australia if rainfall exceeds 50 mm per month (Mc William, 1962). Both the tetraploid and hexaploid races of P. arundinacea are more tol­erant of excess aluminium in acid soils than P. aquatica ; acid­ity is an increasing problem in the region (Culvenor et al., 1986). However neither race of P. arundinacea can survive the summer droughts characteristic of the modified Mediterranean climate. Also, the F 1 of P. aquatica with 6x P. …

Evaluation Of Annual Medics And Subclovers In Oklahoma, S Christiansen, T Svejcar

IGC Proceedings (1977-2023)

Oklahoma has a continental climate with cold winters and a late spring or early-summer rainfall peak. Kneebone (1959) found little justification for attempts to use native legumes for revegetation purposes in western Oklahoma rangelands. Den­man et al. (1961) evaluated 54 genera, 216 species and 1,366 entries of legumes in Stillwater, Oklahoma between 1951 and 1959. They concluded that only alfalfa and some vetches (Vicia spp.) had any forage potential. Most clovers and medics failed to survive the winter cold.

Subclover is largely but not wholly Mediterranean in its dis­tribution (Morley, 1961) and has been grown on limited hecta­rages in the …

Introduction And Evaluation Of Tropical Forages In Various Ecosystems Of Costa Rica, E A. Pizarro, S Diulgheroff, P Argel

IGC Proceedings (1977-2023)

In 1987, three germplasm screening sites were established in Costa Rica for Central America and the Caribbean islands. They represent typical agroecological conditions where cattle are raised : namely subhumid, seasonal and humid tropics. Field work in 1987-88 concentrated on establishing grasses and legumes for trial evaluation of 31 genera and 88 species for a total of 790 accessions. Seed multiplication plots (9 ha) of promising materials were also established, as well as grazing tri­als and on-farm research activities. Preliminary results showed that some accessions of Andropogon gayanus, Brachiaria spp, Panicum maximum, Cen­trosema brasilianum, Arachis pintoi and Desmodium ovalifolium have …

The Study On The High Yield Property Of Billion Dollar Grass, Wan Lishong, Liu Shenglin, Geng Renren, Shao Shengrong, Jiang Wenkui

IGC Proceedings (1977-2023)

In 1964, one plant of billion dollar grass (Echinochloa crus­galli Link) was found by Wan Lisheng in artificial grassland in mid-part of the desert steppe in Ningxia, China. 50 g of seeds were collected in the same year. After 24 years' systematic selec­tion breeding, a new variety named Hai zi-1 billion dollar grass (BDG) was developed. The characteristics of the grass were high-yield and fine quality with extraordinary plant height. The average height of the community was 180-230 cm, the highest plant could be 250 cm high. Its field yield was 16,866 t/ha DM in Ningxia plain irrigated area …

Cynodon Dactylon Pers. A Common Fodder Grass Of Grasslands Of The Upper Gangetic Plain Of India, H R. Sant

IGC Proceedings (1977-2023)

The grasslands of the Upper Gangetic Plain of India are composed ofUttar Pradesh, Bihar and Bengal, and this area is fertile. The chief climatic factors, the temperature and rainfall together are responsible for a distinct type of vegetation. The rainfall is less than 70 cm. in west Uttar Pradesh being more than 150 cm. in Bengal.

In India, natural grasslands are hardly present, and most of them are maintained in their present serial stages due to biotic influence. Hence the grasslands occupy vast chunks of land in the outskirts of villages. Given proper care and managements either for available cultivation …

Observations Sur La Repartition Et L’Ecologie De Luzernes Annuelles Et De Trefle Souterrain En Corse, J M. Prosperi, V Gensollen, I Olivieri, P Mansat

IGC Proceedings (1977-2023)

Des missions de prospection du genre Medicago, realisees entre 1985 et 87, ont permis de mieux connaitre !es relations especes-milieux, pour mieux cerner la variabilite de ces especes, leur distribution et la gamme de milieux favorables a chacune d'entre-elles.

Grass Adaptation In Cuba. Ii. Regional Results With New Cultivars, J J. Paretas

IGC Proceedings (1977-2023)

In Cuba, bovine feeding is based on the maximum pasture and forage utilization. Pastures occupy approximately 3.0 mil­lion hectares, the highest agricultural area of the country. From there, one million hectares are sown with improved varieties and the rest with low yielding and poor quality natural species or shrub areas with a very poor utilization area (Paretas and Carballar, 1988). On considering the high genetic potential of the animals mainly pures or with a high Holstein blood percentage, empha­sis is made to transform the areas dedicated to pasture by improving the varieties yielding more and with a more stable production …

Comparative Study Of Some Varieties Of Cowpea I- Productivity And Nutritive Analysis, K M. Ghobrial, M A. Gabra

IGC Proceedings (1977-2023)

In Egypt, the serious problem of feed shortage, especially of green summer fodder suppresses the improvement of animal production. Therefore, dependence on improving local food and food resources for both animals and humans becomes a «must» for a right policy. The animal feeding system is depen­ding on the cultivation of berseem (Trifolium alexandrium L.). It produces annually around 4.81 million tons starch value/year and could cover the requirements of animals with surplus of 0.92 million tons starch value. However, in summer period, there will be at least a deficiency of 1.50 million tons starch value and most animals are …

Synthese De La Recherche Sur Les Especes Annuelles De Medicago En Elgerie, L Adem

IGC Proceedings (1977-2023)

En Algerie, ii existe pratiquement une dichotomie entre la cerealiculture dans la zone Nord (300 a 500 mm de pluie) et l'elevage ovin relegue en zone steppique (250 mm de pluie). Le cheptel ovin ne peut survivre uniquement sur !es maigres res­sources de la steppe; !es apports de fourrages secs et !es migra­tions estivales vers le Nord restent necessaires. Pour !'integration cerealiculture-elevage, la creation des piiturages annuels de Medicago au depens des jacheres impro­ductives (mains de 250 UF/ha) etait imperative et a debute des octobre 1972. Ces piiturages ameliores contribueraient a reduire un deficit de 3 milliards d'UF sur un …

Early-Maturing And High-Yielding New Pea Varieties Zhongwan N1, N2, N3, And N4, Yunyue Sun, Jiakai Su

IGC Proceedings (1977-2023)

Pea is one of the main edible beans for the Chinese people. The total output of pea in China is third only to that of soybean and broad bean. In the main producing area, pea is a protein supplement feed for the animals and poultry next to bean meal. However, the planting area was restricted because most of the old varieties have long growing periods. The yield is low, the seed quality is poor, the plant is high, so it is easy to lodge. Therefore we selected and bred new pea varieties with early­maturing,' high-yielding, low-plant and erect as well …

Seeds Mixtures For Upland Grassland In The West Of Scotland, G.E D. Tiley

IGC Proceedings (1977-2023)

Improved grassland swards for the hills and uplands of Bri­tain must be able to withstand the exacting conditions of a difficult environment. Longevity and botanical stability are particular requirements under harsh growing conditions, high grazing pressures, low maintenance and restricted manuring. Herbage species and varieties suitable for sowing in improved hill and upland grassland have been identified in previous studies (Davies et al., 1984). Further screening of modern varieties for upland swards has taken place recently in the west of Scotland (Tiley and Frame, 1984). A selection of the best of these varieties was incorporated into simple seeds mixtures for …

Productivity And Shade Tolerance Of Axonopus Spp., Paspalum Spp. And Stenotaphrum Secundatum In The Humid Tropics, J M. Toledo, A Arias, R Schultze-Kraft

IGC Proceedings (1977-2023)

The native grasslands that result from degradation of introduced pastures following deforestation are largely comprised of the species Axonopus affinis, A. compressus, Paspalum conjugatum, P. notatum, P. pilosum, P. plicatulum and Stenotaphrum secundatum. Together with unpalatable grasses such as Imperata spp. and Homolepis spp., they consti­tute a disclimax vegetation induced by over-grazing and weed control (Toledo, 1984). Such induced grassland communities occur in open and shaded areas under grazing throughout the humid tropics of Latin America, Africa and Southeast Asia (Sajise, 1980). This paper reports on the assessment of the seasonal yield potential and shade tolerance of 37 accessions …

Contribution A L’Etude Des Especes Spontenees Du Genre Medicago L. En Algerie, Variabilite Au Niveau Des Graines Et Des Gousses Chez Sept Populations De M. Scutellata; Relation Avec Les Conditions Du Milieu D’Origine, A Abdelguerfi

IGC Proceedings (1977-2023)

Dans le but de resorber la jachere, de proteger les sols contre l'erosion, d'ameliorer la production des parcours et dans un souci de valorisation des ressources phytogenetiques locales d'interet fourrager, plusieurs travaux ont ete menes sur !es luzernes annuelles (Abdelguerfi, 1978 ; Abdelguerfi et al., 1988a et 19886). L'un des interets majeurs des especes annuelles du genre Medicago reside dans leur utilisation au niveau des jacheres. Grace a leurs graines dures, elles entrent facilement en rotation avec !es cereales. Mais la longevite du systeme ble/Medicago est conditionnee par la connaissance des elements se rapportant a la production de graines par …

The Performance Of Wheatgrass Cultivars In Inner Mongolia Of China, Yun Jing-Feng, Mi Fu-Gui

IGC Proceedings (1977-2023)

Crested wheatgrass (Agropyron J. Gaertn) is native to Eurasia and most commonly occurs in southern regions of the U.S.S.R., northern regions of China and the P.R. of Mongolia. It is a main species component of steppe, sandy regions of steppe and mountain vegetation. Crested wheatgrass is a very winter-hardy, drought-resistant, extremely long-lived perennial bunchgrass. It regrows very early in the spring and turns yellow very late in the fall, main­taining a period of green growth more than 7 months. It is more widely used for rangeland improvement and artificial pasture establishment in the arid and semi-arid regions. There are …

The Development Of Murex Medic As A New Pasture Species For Acid Soils In Australia, D J. Gillespie

IGC Proceedings (1977-2023)

Until recently murex medic (Medicago murex) was not con­sidered to be particularly useful as a pasture species anywhere in the world. However, the identification of several unique characteristics possessed by this species has stimulated interest in its use. The first registered variety, Zodiac, was developed by the Western Australian Department of Agriculture and released to seed producers throughout Australia in 1988. Other varieties are being evaluated and further releases are likely in a few years. The Western Australian Department of Agriculture now holds the world's largest collection of the murex species with approximately 450 introductions from the Mediterranean …

Ontribution A L’Etude Des Especes Spontanees Du Genre Medicago L. En Algerie. Analyses Chimiques Du Fourrage Au Stade Vegetatif, Ratiba Goumiri, A Abdelguerfi, F H. Longo-Hammouda, S Oubchur

IGC Proceedings (1977-2023)

En Algerie, l'alimentation constitue le principal facteur limi­tant la production animale; son deficit en unites fourrageres (UF) est evalue a 3 milliards (Moskal, 1983). Elle est, outre son deficit, souvent de tres mau��aise qualite. La connaissance de la valeur alimentaire des fourrages est indispensable pour equilibrer au mieux !es rations, etablir des plants de rationnement adaptes aux besoins et valoriser le potentiel genetique du troupeau (Codron, 1986). Dans ce cadre et afin de caracteriser le materiel vegetal local, nous avons realise quelques analyses classiques sur des legumi­neuses du genre Medicago. Les especes de ce genre sont, en effet, appelees …

Introduction And Evaluation Of Tropical Forages In The Savannas Of Colombia, E A. Pizarro, L H. Franco, A Ramirez

IGC Proceedings (1977-2023)

The well-drained isohyperthermic savannas occupy an area of 98 million hectares, and are distributed in Colombia, Venezuela, northern Brazil, and Guyana. This extensive region of tropical America is characterized by a total wet season potential evapotranspiration of 901 to 1060 mn, an average monthly temperature in the wet season above 23.5 °C, and a wet season of six to eight months. The soils are Oxisols of low fertility and the predominant production system is extensive cattle ranching on native pastures of low nutritive value (Coch­rane et al., 1985). The Tropical Pastures Program of CIAT began a series of regional trials …

The Potential Of Secondary Grasses, J Frame

IGC Proceedings (1977-2023)

The influence of invasive grass genera, such as Festuca, Agrostis, Holcus et al., on the productivity of sown swards is subject to controversy. Some authors have classed most unsown grasses as "weeds" while others (e.g. Frame, 1983) have classed certain of them as "secondary" grasses since they can be more productive than sown "primary" grasses such as Lolium perenne L., especially under adverse environments and low soil fertility conditions. Thus the production and quality or the grass species which most commonly invade UK grassland or are typical of permanent pasture were assessed at Ayr, longi­tude 4°33' west and latitude 52°28' …

Centrosema Tetragonolobum- A New Tropical Pasture Legume For Acid Soils, R Schultze-Kraft

IGC Proceedings (1977-2023)

During one of the joint plant exploration missions between CIA T's Tropical Pastures Program and national research institutions which aim at building up a comprehensive inter­national forage germplasm collection for development of acid­soil tolerant cultivars (Schultze-Kraft, 1985), an unknow Cen­trosema species was collected. It is closely related to C. brasili­anum and was recently described as C. tetragonolobum (Schultze-Kraft and Williams, in press). Its natural distribution is restricted to the Orinoco region in Colombia and Venezuela between latitudes 4° and 6° N. At present 12 germplasm accessions are available. They were collected during 1984-86 on acid soils (pH 4.5-5.5) and in …

L’Amatante (Amaranthus Retroflexus L.) Comme Plante Fourragere, L Bosch, F Casanas, A.M.C Verdu

IGC Proceedings (1977-2023)

L'amarante est une des mauvaises herbes !es plus communes dans nos champs. Elle parvient a etouffer la culture principale si on ne la contr6le pas correctement. Elle a une germination maximale en fin de printemps et en debut d'ete, bien que la ger­mination continue pendant tout l'ete, favorisee par Jes hautes temperatures et la lumiere intense (Baskin et Baskin, 1977). Sa croissance rapide s'explique par le fait qu'il s'agit d'une plante en C-4 specialement efficace pour la captation de CO2 puis­qu'elle a des cloisons cellulaires tres minces (Longstreht et al., 1980). Elle presente aussi une remarquable capacite de repousse apres …

Morpho-Physiological Aspects And Nutritive Value Of Brachiaria Brizantha Cv. Marandu And Heteropogon Sp Affected By The Plants' Age, V. De B.G Alcantara, A.R P. De Almeida, P B. Alcantara, G Braun, E L. Caielli

IGC Proceedings (1977-2023)

Grazing pressure must be related to the pasture potential capacity of recovery. The measurement of leaf area index (LAI) is a way of evaluating that effect. Whatever the management, the main objective will be to allow pasture to reach a high LAI status and its' maintenance (Peterson, 1970). In elephant grass the stem/leaf ratio was used to indicate the dry matter production and indirectly indicates the grazing pressure (Rodrigues, 1984). Present experiment was done to evaluate the evolution of leaf area index (LAI), leaf/stem ratio (L/S), percentages of crude protein (CP), crude fiber (CF) and in vitro dry matter digesti­bility …

Forage Legume Productivity In A Medium Altitude Acid Soil Area Of Ethiopia, J R. Lazier

IGC Proceedings (1977-2023)

The medium altitude (1000 - 2000 m) acid soil regions of East Africa are preferred agricultural areas due to the adaption of coffee and many food crops to the environment. In the Soddo, Wolaita area of Ethiopia population densities are high and farm size averagess about l ha. There is a lack of high quality feed in the area for the cattle which are an integral part of the farming system. A trial was designed to test the productivity of promising legumes in mixture with a commercial cultivar of a grass dominant in the region for cut and carry feeding …

Study Of Forage Plants' Initial Growth Using The Quantitative Development Analysis, V. De B.G Alcantara, A.R P. De Almeida

IGC Proceedings (1977-2023)

The initial development analysis is destinated to the evalu­ation of net production in plants, derivated from the photosyntetic process and the perform results of the assimilat­ive system during certain time period (Watson, 1952). The factors that guide plant production, in general, may be classificated in three classes : genetic, ecological and physiologi­cal factors. The physiological factors are : leaf area index (LAI), net assimilation rate (EA) and relative growth rate (Rw) (Alvim, 1962). Some authors think that little genetic difference exist in relation to EA and that there is a little probability of increasing the production capacity of species through …

The Development Of Medicago Polymorha L. As An Important Pasture Species For Southern Australia, M A. Ewing, J G. Howieson

IGC Proceedings (1977-2023)

Despite the importance of annual pasture legumes to the farming systems of southern Australia and efforts to select appropriate species and varieties (Cocks et al., 1980), well adapted pasture legumes have not been identified for all situa­tions. A particular need exists for species and varieties suited to light surface textured, acid soils in areas receiving between 250 -400 mm of rainfall annually. Soils of this general description are widespread in Western Austrafo, .. Subterranean clover performs well on similar soils where they occur in higher rainfall zones but often fails to persist in arid areas, especially where frequent cereal cropping …

Negative Correlations Between Resource Allocation To Survival And Reproduction: Comparisons Between Annual And Perennial Species Of Medicago For Juvenile Vigor, I Olivieri, A Bory, F Angevain, M Angevian, J M. Prosperi, P Mansat

IGC Proceedings (1977-2023)

At any given age, a plant must allocate limited resources to growth, survival (e.g., disease resistance, root storage) and reproduction (through male and female functions). Growth may be viewed as a way of acquiring more resources (necessary for survival or reproduction at a later time). Response to selec­tion, whether natural or artificial, may well depend on the shape of the compensation curves that exist between those functions (Olivieri, 1987). Such a principle of resource allo­cation predicts the existence of negative correlations between these components of the life-cycle (see for instance Roach, 1986). As shown by Van Noordwijk and De Jong …

Contribution A L’Etude Des Especies Spontanees Du Genre Scorpiurus L. En Algerie Ii. Durete Et Germination Des Graines Chez 29 Populations De S. Muricatus Subsp. Sulcatus (L.) Thell, M M'Hammedi-Bouzina, A Abdelguerfi, R Berrekia

IGC Proceedings (1977-2023)

Les especes du genre Scorpiurus L., tres recherchees par le cheptel, peuvent jouer un role important dans !'amelioration des parcours et de la production des jacheres. Outre leur inten��t fourrager, elles concourent au maintien de la fertilite des sols grace a leurs caracteristiques agronomiques (fixation d'azote, systeme racinaire puissant, port etale ... ). Mais !'utilisation de ces especes spontanees de legumineuses reste conditionnee par !'estimation de la proportion de graines dures et Jes moyens a mettre en ceuvre pour surmonter cet obstacle a la germination. Ainsi, et suite aux travaux de Bensalem et al. (1988) sur le genre Scorpiurus et …

Grass Adaptation In Cuba. I. Characterization Of The Areas Dedicated To Livestock Production, J J. Paretas

IGC Proceedings (1977-2023)

The present study is aimed to point out various aspects allowing to locate and learn the soil, climate, social and econ­omic conditions as well as the production characteristics of pastures and forages and their utilization for milk and beef pro­duction under Cuban conditions.

Perennial Legumes And Grass-Legume Associations Adapted To Poorly Drained Savannas In Tropical South America, B Grof, D Thomas, R P. De Andrade, J.L F. Zoby, M A. De Souza

IGC Proceedings (1977-2023)

Seasonally flooded areas and swamp grasslands constitute a significant percentage ot the savannas and represent an import­ant source of supplementary forage during the dry season. Approximately 21 % (170 million ha) of the central lowlands of tropical South America is poorly drained ; 82 % of these lands (139 million ha) is covered with forest and the remaining 31 million ha by native savannas (Cochrane et al.,1985). The poorly drained savanna lands have been used success­fully since colonial times for extensive cattle production. Sig­nificant areas are found in the Brazilian Pantanal, in Brazil's southwest Amazonia, the Casanare plains of northeast …